Polishing composition and polishing method using the same

Abstract

The present disclosure provides a polishing composition containing: abrasive grains having surfaces modified with a silane coupling agent and having a positive surface potential, and having an average secondary particle size of 45 nm or more and 100 nm or less, and a silanol group density of more than 0.0/nm2 and 3.0/nm2 or less; a surfactant which is an alkyl phosphate having 6 to 18 carbon atoms; and an aqueous dispersing medium.

1 . A polishing composition comprising:
 abrasive grains having surfaces modified with a silane coupling agent and having a positive surface potential, and having an average secondary particle size of 45 nm or more and 100 nm or less, and a silanol group density of more than 0.0/nm2 and 3.0/nm2 or less;   a surfactant which is an alkyl phosphate having 6 to 18 carbon atoms; and   an aqueous dispersing medium.   
     
     
         2 . The polishing composition according to  claim 1 , further comprising a pH adjusting agent. 
     
     
         3 . The polishing composition according to  claim 2 , wherein the pH adjusting agent is a carboxylic acid (other than amino acid), or an amino acid. 
     
     
         4 . The polishing composition according to  claim 3 , wherein a number of carbon atoms of the carboxylic acid is an even number. 
     
     
         5 . The polishing composition according to  claim 3 , wherein the amino acid is an acidic amino acid. 
     
     
         6 . The polishing composition according to  claim 1 , wherein a pH value of the polishing composition is within a range of 3 to 5. 
     
     
         7 . The polishing composition according to  claim 1 , wherein a concentration of the surfactant is 0.1 to 1.0 g/L. 
     
     
         8 . The polishing composition according to  claim 1 , wherein the abrasive grains are modified with a silane coupling agent having an amino group. 
     
     
         9 . The polishing composition according to  claim 8 , wherein the silane coupling agent is (3-aminopropyl)triethoxysilane (APTES). 
     
     
         10 . A polishing method comprising the steps of:
 providing a polishing apparatus comprising a polishing pad and a polishing head;   setting an object to be polished between the polishing pad and the polishing head; and   polishing the object to be polished by using the polishing composition according to  claim 1 .   
     
     
         11 . The polishing method according to  claim 10 ,
 wherein the object to be polished is a substrate comprising a first surface facing the polishing head and being an outermost surface, and a second surface located under the first surface, and   wherein the object in which at least a metal nitride is present on the second surface of the substrate is polished.   
     
     
         12 . The polishing method according to  claim 11 , wherein the metal nitride comprises titanium nitride (TiN). 
     
     
         13 . A method for producing a semiconductor substrate comprising the polishing method according to  claim 10 .